The present invention relates to devices for measuring vibratiion parameters and, more particularly, to pickups for measuring vibration parameters of operating machinery parts, including such parameters as impact pressures, accelerations, forces, impact loads, etc.
There is known a pickup for measuring vibration parameters of operating machinery parts, which is a single-component piezopickup for measuring acceleration components of mechanical vibrations of an operating machine.
This known pickup comprises a housing shaped as a cylindrical body of revolution, with a sensitive piezoelement arranged inside the body, the sensitive axis of the sensitive element extending, as a rule, along the axis of the housing. The pickup housing is provided with a thread or a threaded pin hole to receive a pin, the pin hole and the pin being intended for mounting the pickup on a part being tested, which part has a corresponding threaded hole.
This only measures one acceleration component (longitudinal or transverse) at the place where it is mounted on a stationary element or part of an operating machine or mechanism. Mounting the known pickups on fast-rotating parts (parts rotating at a great rotation frequency) is extremely complicated since it involves modifying the part being investigated and removing some material to ensure the pickup mounting, which, in turn, alters inertia and rigidity characteristics of the part being investigated and unbalances rotating parts. Moreover, the attachment of the known pickup to fast-rotating parts and units is extremely unreliable, as the pickup is structurally unfit for being mounted on fast-rotating parts.
There are also known multicomponent piezoelectric pickups intended for simultaneously measuring several acceleration components at one point on a stationary part or unit of an operating machine or mechanism.
It is impossible to mount such pickups on fast-rotating parts due to the great size and weight of these pickups. Also, mounting of the pickup requires a flange and a number of screws to secure the pickup.
In addition, multicomponent piezoelectric pickups are practically inapplicable for vibroacoustic investigation, for the method of dividing spatial vibrations of rotating parts requires successively taking off, at one point of a part being investigated, and, preferably, by one sensitive element, an electric signal which is proportional to either longitudinal or transverse torsional, or radial vibrations of the part under investigation.